Overshot for controlling wild wells



y 1957 J. E. ECKEL.

OVERSHOT FOR CONTROLLING WILD WELLS Filed March 24, 1955 FIG.' 3

FIG-2 FIG"! John E. Ecke! Inventor By ,4 714. Attorney of this inventionis shown in place over the well.

2,793,700 9 OVERSHOT non CONTROLLING WILD WELLS John E. Eckel, Tulsa,Okla., assignor to Esso Research and Engineering Company, a corporationof Delaware Application MarchZ l, 1955, Serial No. 496,367 2 Claims.(Cl. 166-.95)

The present invention concerns apparatus for closing off a wildpetroleum well. More particularly the invention relates to an overshotdevice that can be lowered into place over a wild well and quicklyattached to the casing of the well to seal the same.

With any high pressure producing oil well there is always the dangerthat the Well will get out of control and that the well cannot be closedoff with the existing equipment, For example when a well is beingdrilled or repaired the pressure control equipment may become damaged orbroken off, so that the pressure of the well can no longer be confined,resulting in a wild Well from which gas and oil will rapidly escape andproduce a fire hazard, endanger surrounding property and human life, andcause enormous waste of a valuable natural resource. Equipmentheretofore used for bringing such a well under control has required thatworkmen must get close to the well and manipulate the equipment by handso that there is an accompanying safety hazard.v

It is an object of the present invention to provide equipment that canbe lowered into place over a wild well and quickly attached by remotecontrol. In accordance with the present invention an overshot apparatusis provided which will fit over the existing casing of the well andwhich can be quickly connected and sealed by expansible packing meansafter which conventional blowout prevention equipment attached to theupper end of the apparatus can be closed to shut off the well and thewell then killed in a conventional manner. The apparatus is particularlyuseful for wells in marine locations.

The nature of the apparatus of this invention will be readily understoodwhen reference is made to the accompanying drawings in which:

Figure 1 is an elevational view partly in section showing the manner inwhich the device can be attached to well casing,

Figure 2 is an enlarged view of a portion of the ap paratus of Figure 1showing the packing member in its deflated position; and

Figure 3 is an enlarged view, similar to Figure 2, showing the packingmember in its inflated condition.

Referring now in particular to Figure 1 the apparatus The elements ofthe well that are shown include the surface casing 10 which extendsabove the surface of a body of Water 13 and which is surrounded by aconductor pipe 11. The annulus between the surface casing and theconductor pipe is filled with cement 12, the purpose of the outerconductor pipe and the cement seal being to prevent salt water attack onthe surface casing. This is common practice for wells that have beendrilled into tted t Patent ice type saws, artillery, powerful cranes orother means the interfering surfacefittings such as tubingheads,flowmari The apparatus itselfcomprises a cylindrical body 17 the top ofwhich is provided with a flange 18 to which 7 have been attachedconventional blind ram blowout pre- 7 venters 19. A bail 20 fastened tothe top of the appa ratus enables the apparatus to be supported fromacrane so that it can be swung into place over the well and centered bymeans of lateral winch lines attached to the side brackets 24. g

A lining of cement or other suitable material 21 is provided within thecylindrical body over most of its length to absorb the abrasion thatwill occur from rock particles that are carried up from the well in thestream of escaping oil and gas. Mounted within the lower end of thecylindrical body is an annular expansible paclo.

ing member 25 having an annular cavity 26 accessible through. the inletport 28 so that the packer can be inflated to provide a fiuidtight sealin the annulus between the casing and the cylindrical body after theapparatus has been lowered into place. Attached to the inlet pipe 28 bymeans of a check valve union S ll is a high pressure hose 31 throughwhich hydraulic pressure may be exerted to inflate the packing member.The purpose of the check valve union is to provide for rapid and easydisconnecting of the high pressure hose after the packer has been set.The check valve will of course be placed in that portion of the unionthat is connected to the port 28. Suchcheck valve unions arecommercially available and hence this element is not shown in detail. Toprevent damage to the check valve union there are provided a pair ofguard plates 32 positioned above and below the union.

A plurality of reinforcing ribs 34 are imbedded in the materialconstituting the packer and are pivotally attached to the cylindricalbody by means of pins 35. It will be seen from a comparison of Figures 2and 3 that these reinforcing ribs extend inwardly from the cylindricalbody toward the well casing when the packer is inflated. These ribs aredistributed about the circumference of the packer and serve to reinforcethe packer.

Bonded to a lower portion of the packer are a plurality ofcircumferentially distributed support bars 37 each of which is pivotallyattached to the body 17 by means of pins 39. Pivotally supported to theouter end of each of the bars 37 is one of a set of slips 36 whichengage the wall of the casing when the packer is inflated and therebyprevent slippage between the cylindrical body 17 and the casing afterthe packer has been set. After the slips have been set, downward travelof the support bars 37 is prevented by the upward facing shoulder 40 onthe inside of the cylindrical body 17. It may be seen that these slipswill hold the overshot in position even if casing head 14 and all otherprojecting shoulders have been removed from the casing. It is of courseusually desirable, however, to take advantage of the extra supportprovided by such projections, such as the shoulder of the casing head 14and the projecting plugs 33, when such are present.

After the apparatus has been set over the Well and the packer has beeninflated to seal the apparatus to the easing the blowout preventers 19are closed in the usual manner. A suitable line is then connected tovalve 23, after which the valve is opened and a conventional dense wellkilling fluid is pumped into the well through the port 22. After thewell has been killed the necessary repairs to the well can be made.

It is to be understood that the embodiment of the I invention hereindescribed has been presented by way of example and not of limitation andthat modifications thereof are contemplated Within the scope'of theinven tion as defined by the appended claims.

What is claimed is:

1. An overshot apparatus for use in shutting off flow from a cased wellhaving casing extending upward out of the Well which comprises acylindrical body adapted to be lowered andfit over the casing, meansoperable to close off the upper end of said cylindrical body, anexpansible packing member fixed to the inner periphery of saidcylindrical body adjacent the lower end thereof, a plurality of supportbars each pivotally attached at one end to the inner peripheral surfaceof said cylindrical body and adjacent said packing member, a slip memberattached to the opposite end of each support bar and References Cited inthe file of this patent UNITED STATES PATENTS 910,295 Layne Jan. 19,1909 1,323,660 Thrift Dec. 2, 1919 1,586,923 Townsend June 1, 1926 Smithet a1 Feb. 21, 1939

